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Václav Hauser

  • Hesslerová, P., Chmelová, I., Pokorný, J., Šulcová, J., Kröpfelová, L., & Pechar, L. (2012). Surface temperature and hydrochemistry as indicators of land cover functions. Ecological Engineering, 49, 146-152. doi:10.1016/j.ecoleng.2012.08.029

This paper presents an integrated approach to landscape functioning assessment combining energy efficiency and hydrochemical balance studies. Energy balance is expressed by surface temperature while hydrochemical balance is illustrated by electric conductivity and selected hydrochemical parameters. Six model sub-watersheds with different land use situated in southern Bohemia were chosen to show the influence of landscape management on landscape functioning. The watersheds with higher humankind activity were shown to have both higher and more fluctuating average surface temperature as well as higher electrical conductivity in the runoff surface water. Watersheds with the predominance of forests and meadows showed opposite trends in the monitored parameters. Our results show that sustainable landscape management leads to lower temperature extremes and consequently to low matter and water losses. Large improvements of energy and matter balance can be achieved by restoration of permanent vegetation and/or effective water retention and accumulation.

Solar energy distribution;, Landsat TM; Water electrical conductivity; Catchment; Sustainable landscape management

  • Musil, M., Novotná, K., Potužák, J., Hůda, J., & Pechar, L. (2014). Impact of topmou2012th gudgeon (Pseudorasbora parva) on production of common carp (Cyprinus carpio) — question of natural food structure. Biologia, 69(12). doi:10.2478/s11756-014-0483-4

Four production fishponds in the Czech Republic were investigated in 2003 and 2004 during a feeding experiment on common carp (Cyprinus carpio). In 2003, topmouth gudgeon (Pseudorasbora parva) was detected in enormous amounts in all of the investigated fishponds. P. parva got into the fishponds spontaneously by water inflow from connecting channels. The objective of this paper is to describe the condition of natural food in the presence of P. parva and its subsequent effect on carp production. The estimation of the population density of P. parva achieved at least 44 kg/ha in 2003. In 2004, precautions against P. parva invasion were taken and its presence wasn?t recorded during the season. The impact of P. parva on natural food structure was described in terms of zooplankton and zoobenthos amounts and main fish production parameters. A special focus has been taken on the density of Daphnia genus and chironomid larvae, the most preferred zooplanktonic and zoobenthic groups in feed of P.arva,respectively. In 2003,P.parva suppressed the zooplankto npopulations significantly, especially large cladocerans of the Daphnia genus. Influence of P.parva on zoobenthos structureand density was not detectable. Unfavorable natural food condition in 2003 caused extremely low carp production whichfell to the mean value of 283 kg ha−1and food conversion ratio reached 3.5. On the contrary, in 2004 the mean carp production and food conversion ratio attained 634 kgha−1and 1.6, respectively. The results described harmful competitive effect of huge populations of P.parva and its surprising economic consequences. Costs per 1 kg of growth were increasedby approximately 100% in 2003 compared with results from season 2004.

Biological invasion; carp production; natural food; Pseudorasbora parva; zoobenthos; zooplankton

  • Hlaváč, D., Másílko, J., Hartman, P., Bláha, M., Pechar, L., Anton-Pardo, M., & Adámek, Z. (2015). Effects of common carp (Cyprinus carpio Linnaeus, 1758) supplementary feeding with modified cereals on pond water quality and nutrient budget. Journal of Applied Ichthyology, 31(Suppl. 2), 30-37. doi:10.1111/jai.12850

This 4‐month study (10 May – 6 September 2012) evaluated the effects of supplementary feeding on common carp (Cyprinus carpio Linnaeus, 1758) growth, water quality, natural food availability and nutrient balance under different pond treatment regimes (eight rectangular earthen ponds; 0.03 ha surface area; 3‐year‐old carp). The nitrogen and phosphorus budgets were calculated as the difference between input (food, fish stocked and influent water) and output (effluent water and fish harvested). Three types of supplementary feeds were used: wheat, thermally‐treated wheat, and thermally‐treated and pressed wheat. An additional test group was provided with naturally available forage only and served as a control. The type of supplementary feed did not influence the water quality, with the exception of dissolved oxygen. No significant differences among experimental ponds were observed in zooplankton abundance. The use of modified cereals (especially thermally‐treated and pressed wheat) improved carp growth performance and resulted in lower nutrient concentrations in effluent water via improving their digestibility. Both thermally‐treated and thermally‐treated and pressed cereals improved the balance of phosphorus; hence these diets could be beneficial, not only from the fish production point of view but also as a tool to reduce the deterioration of pond water quality.

Carp production; natural food;

  • Hesslerová, P., Pokorný, J., Brom, J., & Rejšková – Procházková, A. (2013). Daily dynamics of radiation surface temperature of different land cover types in a temperate cultural landscape: Consequences for the local climate. Ecological Engineering, 54, 145-154. doi:10.1016/j.ecoleng.2013.01.036

Surface temperature (Ts) is directly related to the capacity of every ecosystem to direct energy to different heat fluxes. Vegetation with a sufficient supply of water is able to cool down the surface by enhancing the latent heat flux via evapotranspiration. We chose seven types of land covers common in a temperate agricultural landscape and used a combined method of airship thermal scanning of Ts and ground measuring of thermodynamic Ta to show their Ts and Ta (air temperature) characteristics under high solar irradiance and their consequences for local climate; simultaneously we showed that this temperature difference increases with water content. A combined method of airship thermal scanning of Ts and ground measuring of thermodynamic Ta was used. The localities differed markedly in both the values and the dynamics of Ts and Ts − Ta. In the early afternoon the difference in Ts between the different land covers reached almost 20 °C. Ecosystems with non-functional or no vegetation largely resembled the asphalt surface, whereas the ecosystems covered with dense, bushy or tree vegetation showed relatively well balanced daily temperature dynamics with low temperature extremes and a slow temperature morning increase or afternoon decrease. Ts − Ta at the peaking solar irradiance ranged between −1 °C at the forest and 14–17 °C at the dry harvested meadow and the asphalt surface respectively. We highlight the importance of Ts as a measurable indicator of ecosystem and landscape functioning and outline the importance of functional vegetation for climate. Those feedbacks between vegetation, surface temperature, water and climate are crucial in the landscape management, climate change discussions and therefore for decision makers and landscape developers.

Solar energy distribution; Water; Vegetation; Climate; Airship thermal scanning

  • Ellison, D., Morris, C. E., Locatelli, B., Sheil, D., Cohen, J., Murdiyarso, D., . . . Sullivan, C. A. (2017). Trees, forests and water: Cool insights for a hot world. Global Environmental Change, 43, 51-61. doi:10.1016/j.gloenvcha.2017.01.002

Forest-driven water and energy cycles are poorly integrated into regional, national, continental and global decision-making on climate change adaptation, mitigation, land use and water management. This constrains humanity’s ability to protect our planet’s climate and life-sustaining functions. The substantial body of research we review reveals that forest, water and energy interactions provide the foundations for carbon storage, for cooling terrestrial surfaces and for distributing water resources. Forests and trees must be recognized as prime regulators within the water, energy and carbon cycles. If these functions are ignored, planners will be unable to assess, adapt to or mitigate the impacts of changing land cover and climate. Our call to action targets a reversal of paradigms, from a carbon-centric model to one that treats the hydrologic and climate-cooling effects of trees and forests as the first order of priority. For reasons of sustainability, carbon storage must remain a secondary, though valuable, by-product. The effects of tree cover on climate at local, regional and continental scales offer benefits that demand wider recognition. The forest- and tree-centered research insights we review and analyze provide a knowledge-base for improving plans, policies and actions. Our understanding of how trees and forests influence water, energy and carbon cycles has important implications, both for the structure of planning, management and governance institutions, as well as for how trees and forests might be used to improve sustainability, adaptation and mitigation efforts.

Forest; Water; Energy; Climate; Carbon; Reforestation; Mitigation; Adaptation; Sustainability

  • Hesslerová, P., Pokorný, J., Huryna, H., & Harper, D. (2019). Wetlands and Forests Regulate Climate via Evapotranspiration. In S. An & J. T. A. Verhoeven (Eds.), Wetlands: Ecosystem Services, Restoration and Wise Use (pp. 63-93). Cham: Springer International Publishing

The role of wetlands and forests in climate and climate change is usually considered as a part of their functions as source or sink of greenhouse gases. However, the permanent vegetation in these systems is an active factor that, through the process of evapotranspiration, directly influences climate as well. Wet vegetation transforms solar radiation into the latent heat of water vapour. Evapotranspiration is a powerful tool that has, due to the phase change of water, a double air-conditioning effect in the landscape. In addition, it reduces thermal gradients, mitigates temperature extremes and closes water and mass cycles. Evapotranspiration-condensation processes slow down where there is a lack of water and permanent vegetation. Solar radiation is then transformed into sensible heat. The overheated surfaces warm the adjacent air layer. Warm air rises turbulently upwards and is capable of absorbing higher amounts of water vapour, which is then transmitted to higher levels of the atmosphere where condensation occurs. These processes significantly dry out the landscape. The Intergovernmental Panel on Climate Change (IPCC) reports, however, do not take into account this direct effect of water and vegetation on climate. This chapter explains the direct function of wetlands and the air-conditioning effect of evapotranspiration, which is also illustrated with thermal ground images. The role of forest and wetlands in transport of water from ocean into continents in terms of a biotic pump is discussed on the basis of the literature.

Solar energy; Latent heat flux; Surface temperature; Thermal images; Climate change; Landscape restoration 

  • Hesslerová, P., Pokorný, J., Huryna, H., Seják, J., & Jirka, V. (2021). The impacts of greenery on urban climate and the options for use of thermal data in urban areas Progress in Planning.

Urban greenery substantially influences the distribution of solar energy in urban areas and thus plays an irreplaceable role in creating local climate. This paper introduces the principles of urban vegetation functioning as a perfect air conditioning system that efficiently cools the environment and balances temperatures through evapotranspiration. It is based on the basic physics of energy transformation and known physiological processes of plants. We demonstrate the possibilities of quantification of the air conditioning role of vegetation in energy units, including the assessment and monetary quantification of ecosystem services and examples of different types of thermal data for assessing the urban environment and climate. We offer the possibility of implementing this approach to spatial planning.

Solar energy; Evapotranspiration Ecosystem services; Surface temperature; Air-conditioning; Trees

  • Baxa, M., Musil, M., Kummel, M., Hanzlík, P., Tesařová, B., & Pechar, L. (2021). Dissolved oxygen deficits in a shallow eutrophic aquatic ecosystem (fishpond) – sediment oxygen demand and water column respiration alternately drive the oxygen regime.

Biological processes tend to dominate the oxygen regime of productive waters. However, in shallow aquatic ecosystems, it is unclear whether the oxygen regime is driven by oxygen production and consumption in the water column or by sediment oxygen demand (SOD). In managed eutrophic ecosystems, this question is especially important in the context of extreme daily oscillations of dissolved oxygen (DO) that could breach physiological limits of heterotrophic aerobic organisms. High-frequency measurement of DO, temperature, global radiation (Gl.Rad.), and pH in a 0.6 m deep, 22 ha eutrophic fishpond Rod (Czech Republic) shows that the oxygen regime depended on the ecosystem state. Over the clearwater period in the early season, the DO level reflected ecosystem heterotrophy with relatively low daily DO oscillations. However, during the summer phytoplankton bloom, the fishpond was primarily autotrophic with extreme DO fluctuation. During late summer, a collapse of the phytoplankton bloom and an associated shift towards heterotrophy and DO deficit frequently occur. In-situ mesocosm experiments in Rod fishpond were conducted throughout 2018 and 2019 growing seasons, to address the importance of SOD to the oxygen regime. We enclosed the water column in transparent and opaque/dark plastic cylinders open or closed to the sediment. The results show that the proportional contribution of SOD to total respiration decreased from 70 to 90% at low phytoplankton biomass (expressed as Chlorophyll-a (Chl-a) concentration) to approximately 10% at phytoplankton bloom. At night, the difference between the oxygen consumption in the cylinders with or without sediment was statistically significant, when the concentration of Chl-a was <100 μg·L-1. On the contrary, the difference was not significant when the concentration of Chl-a was >100 μg·L-1. This revealed that the impact of SOD is negligible at high phytoplankton biomass. 

Shallow aquatic ekosystém; Dissolved oxygen; Sediment oxygen demand; Eutrophic water; Fishpond; Oxygen deficit

Likvidace radiačně kontaminované biomasy po havárii JE-distribuce
v krajině, logistika sklizně, využití bioplynovou technologií

Informační centra pro péči o mokřady a vodu v krajině

  • Projekt „Síť environmentálních informačních a poradenských center pro péči o mokřady a vodu v krajině“ byl zahájen v roce 2006 a…
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